1. Field of the Invention
The present invention relates to a magnetic recording medium and production of the same. More particularly, it relates to a magnetic recording medium with good traveling properties and durability and a process for producing the same.
2. Description of the Prior Arts
A magnetic layer is formed on a substrate of a magnetic recording medium by evaporating or sputtering ferromagnetic metal such as iron, cobalt and nickel or their alloy on a substrate film or by bonding magnetic powder together with a binder component to the substrate. When the magnetic recording medium is slid against a magnetic head during recording and reproducing informations, the magnetic layer tends to be abraded. Particularly, a ferromagnetic metal thin layer which has a large coefficient of friction against the magnetic head is easily abraded or damaged, although it has suitable characteristics for high density recording.
To overcome such a defect, it has been proposed and as well as having been the practice to provide various protective layers on the magnetic layer in order to decrease abrasion or damage caused by the magnetic head and to improve traveling properties of the magnetic recording medium. For example, Japanese Patent Kokai Publication No. 143206/1978 proposes application of a film comprising carbon atoms on the magnetic layer, and Japanese Patent Kokai Publication No. 127232/1984 proposes application of a carbonaceous thin layer containing diamond on the magnetic layer. Japanese Patent Kokai Publication No. 157725/1985 discloses a magnetic recording medium having a protective layer made of a cross linked hydrocarbon material with a specific carbon/hydrogen ratio and Japanese Patent Kokai Publication No. 157726/1985 discloses a process for producing such magnetic recording medium.
A magnetic recording medium having the protective layer comprising the carbonaceous material, however, does not have satisfactory traveling property since said protective layer has a large coefficient of dynamic friction and poor abrasion resistance. This is because the traveling property of the magnetic recording medium having the protective layer comprising the carbonaceous material is to a large extent influenced by contents of hydrogen and oxygen in the protective layer. Therefore, control of the hydrogen and oxygen contents is essential in the formation of such protective layer.
In addition, since the carbonaceous material layer has poor adhesivity to the magnetic layer, it is easily abrased in a short period of time and as a result the durability of the magnetic recording medium is not satisfactory.